The fact that either could be charged has caused some commuters to be charged for their rides on credit or debit cards instead of desired Ventra cards. For those who use Ventra's $100 unlimited monthly pass but also have RFID cards in their wallets, this has caused some grief.

JPMorgan Chase & Co., Chicago's largest bank, has heard from hundreds of disgruntled commuters with contactless cards who want the CTA charges redacted from their accounts, a spokeswoman said. Other banks, including Citibank, Bank of America and BMO Harris, also offer contactless cards, but they did not return calls for comment.

Cubic Transportation Systems Inc., the California company that developed and is managing Ventra for the CTA under a $454 million contract, and the CTA said the Ventra fare card reader will charge only one card because of software protections. But that card might not be the one the commuter had intended.

To avoid a trip to the bank or a call to customer service to get unwanted charges removed from a debit or credit card, Chase spokeswoman Christine Holevas suggested these options:

•Don't tap your wallet on the reader. Take the card out before you scan.

•Keep your Ventra card in a separate case or wallet from your other RFID cards.

•Get a non-contactless card from your bank (one without an RFID chip).

•If you've already accidentally charged a debit or credit card, call a bank representative or walk in to get the charges removed.

Some companies, such as Zappos.com, also sell RFID-blocking wallets. They prevent RFID readers from gathering information from cards inside the wallet, assistant buyer Laurie Bittle said. But you can't choose which cards will be protected and which will not — you'd still have to take your Ventra card out of the wallet to scan it.

Bittle and Holevas said that, while convenient, RFID technology isn't overwhelming popular yet.

"These new technologies, they take some getting used to," Holevas said. "They bring great convenience, but you have to be aware of some of the issues that come along with them."

The troubled Ventra fare-payment system took another hit during the Wednesday evening rush hour when some card readers at 60 of the CTA’s 145 train stations failed, resulting in 15,000 free rides for commuters before the problem was fixed, according to the agency.

Angry commuters packed the house at a CTA budget hearing tonight. They aired their grievances over service reductions and the problems with the new Ventra Card payment system. Ongoing glitches with the Ventra system, including double charges and difficult

Catherine Garypie, at the Jackson Street Blue Line stop in the Loop, demonstrates how her federal identification badge triggers the Ventra system to allow her to go through the turnstiles without using a CTA Ventra card. (Chris Sweda, Chicago Tribune)